The Doctor interrupts the power supply allowing Polly to be freed by servant girl Ara who hides her in the temple of Ando. Zaroff explains his plan to raise Atlantis to the Doctor which the Doctor realises will destroy Earth. Zaroff has realised this too but is quite mad so doesn't care. Ben & Jamie escape from the mines with a pair of ship-wrecked sailors who were captured, Sean & Jacko. They emerge from a tunnel into the Temple of Ando a=finding Polly and Ara who brings them food. The Doctor escapes from the lab and meets Ramo, a priest, who is worried about Zaroff's scheme. They go to see King Thous, who hands them over to Zaroff as prisoners.

Rolls along nicely this episode, not bad at all

The start of this episode (and some of the end of the previous one) survives courtesy of the Australian censors, and I can see why they cut it. It's genuinely one of the scariest things seen in Doctor Who with a bound and defenceless Polly about to undergo "The Operation" and with masked doctors approaching her with syringes. That would have scared the living daylights out of me if I'd have seen it at the time. It also proves that you don't get the whole story from the audio! The next episode of this story does survive but there's nothing in it too compare to this!